It is currently Fri Sep 10, 2010 12:47 pm

All times are UTC - 5 hours [ DST ]

  
                     
 

Post new topic Reply to topic  [ 9 posts ] 
Author Message
 Post subject: My latest project - Schematic - Pics (Update)
New postPosted: Sun Dec 07, 2008 11:11 pm 
Offline
Member Number 1
Member Number 1
User avatar

Joined: Fri Jan 05, 2007 8:53 pm
Posts: 1334
Location: South Coast, MA
My Language: English
Here is my latest project, a monoblock audio power amp SE design using the typical and easy to find tubes! I am making it with parts used in past projects, though the box and chassis base plate is a new layout design. The OT is a Hammond 125ESE and sounds pretty good for the price. Its really neat to have these around, tube amps add a warmth to the music and its very enjoyable! I have one in my work shop and have one in my living room too, though this amp is going to replace that one.

I am working on the board layout now and will post that probably next week sometime.


You do not have the required permissions to view the files attached to this post.

_________________
Get your contributing member badge for 2010!
Small Donations Help - PayPal Link
Be sure to note your user name or send me a pm.


Top
 Profile E-mail  
 
 Post subject: Re: My latest project - Schematic - Pics (Update)
New postPosted: Wed Jan 07, 2009 10:27 pm 
Offline
Member Number 1
Member Number 1
User avatar

Joined: Fri Jan 05, 2007 8:53 pm
Posts: 1334
Location: South Coast, MA
My Language: English
I have made some changes to the schematic and have decided to go with only one stage or 1/2 of a 12AX7. I decided to do this just so I could try and sharpen some of my math skills, and load line theory. My goal is to calculate the best values for Rg, Ra(Rp), Rl, Ck and Co based on my voltage. Right now without any load my power rail is seeing 412V. I think this should drop when everything is hooked up, can anyone calculate these values? (OHM's LAW) As I learn this concept better I will be documenting it here. Maybe we will get some input from someone who already knows this better.

Here is what I have so far


You do not have the required permissions to view the files attached to this post.

_________________
Get your contributing member badge for 2010!
Small Donations Help - PayPal Link
Be sure to note your user name or send me a pm.


Top
 Profile E-mail  
 
 Post subject: Re: My latest project - Schematic - Pics (Update)
New postPosted: Fri Jan 09, 2009 10:52 am 
Offline
Moderator
Moderator
User avatar

Joined: Fri Nov 09, 2007 5:55 pm
Posts: 236
Location: Germany
My Language: German
Great work man! It looks very simple xclap

Would be also a great project for me when I finish my other guitar stuff...
but the time xshrug it's very hard at the moment... :-x


Thomas

_________________
Forum Bot, im just cleaning here!


Top
 Profile  
 
 Post subject: Re: My latest project - Schematic - Pics (Update)
New postPosted: Fri Jan 09, 2009 6:59 pm 
Offline
Member Number 1
Member Number 1
User avatar

Joined: Fri Jan 05, 2007 8:53 pm
Posts: 1334
Location: South Coast, MA
My Language: English
Thanks!

Yeah, audio amps are for the most part simple and are really neat to have around. I buy used stereo tuners from the 70's just so I can run my own tube amps. You can also plug CD's, mp3, into them too. Nothing like kicking back in a dimly lit room listing to them and watching the tubes glow!

_________________
Get your contributing member badge for 2010!
Small Donations Help - PayPal Link
Be sure to note your user name or send me a pm.


Top
 Profile E-mail  
 
 Post subject: Re: My latest project - Schematic - Pics (Update)
New postPosted: Sat Jan 10, 2009 6:12 am 
Offline
Moderator
Moderator
User avatar

Joined: Fri Nov 09, 2007 5:55 pm
Posts: 236
Location: Germany
My Language: German
RMS wrote:
Nothing like kicking back in a dimly lit room listing to them and watching the tubes glow!


Yeah you said it very good! I don't know why but that's also one point that makes tubes so special for me "you see the gear working" it's not as a modern HiFi thing with 2 LED's which is buzzing in the background xshrug

I think we can understand each other xfreiendship xmrgreen 8-)

Thomas

_________________
Forum Bot, im just cleaning here!


Top
 Profile  
 
 Post subject: Re: My latest project - Schematic - Pics (Update)
New postPosted: Sat Jan 10, 2009 10:03 am 
Offline
Member Number 1
Member Number 1
User avatar

Joined: Fri Jan 05, 2007 8:53 pm
Posts: 1334
Location: South Coast, MA
My Language: English
Yup thats half the enjoyment!

xbeer

_________________
Get your contributing member badge for 2010!
Small Donations Help - PayPal Link
Be sure to note your user name or send me a pm.


Top
 Profile E-mail  
 
 Post subject: Re: My latest project - Schematic - Pics (Update & Tested)
New postPosted: Tue Jan 13, 2009 12:05 am 
Offline
Member Number 1
Member Number 1
User avatar

Joined: Fri Jan 05, 2007 8:53 pm
Posts: 1334
Location: South Coast, MA
My Language: English
Well, I finally got around to testing and she sounds very good! But I am going to tweak some values just a tad. Once I do that and finalize it I will post all the values and actual operating voltages. Basically I am going to change the 5k's in the power rail to around 1k then the OT then 5k, and remove one since Rp (preamp) is only 100V right now and the cathode seems to like the 1.5k range, though this might change.....I should have some more updates soon.

xugeek

_________________
Get your contributing member badge for 2010!
Small Donations Help - PayPal Link
Be sure to note your user name or send me a pm.


Top
 Profile E-mail  
 
 Post subject: Re: My latest project - Schematic - Pics (Update)
New postPosted: Wed Jan 14, 2009 12:38 am 
Offline
Member Number 1
Member Number 1
User avatar

Joined: Fri Jan 05, 2007 8:53 pm
Posts: 1334
Location: South Coast, MA
My Language: English
Well, its amazing but by changing two power rail resistors I gained 200V at Rp and its a good thing I reduced theses values too since they were drawing too many watts. I new this right off the bat since as soon as I through the power switch I could smell a slight burning smell, and I knew we had too much resistance going on. With the new values all is good and no burning smell at all. xunsure

:-D


You do not have the required permissions to view the files attached to this post.

_________________
Get your contributing member badge for 2010!
Small Donations Help - PayPal Link
Be sure to note your user name or send me a pm.


Top
 Profile E-mail  
 
 Post subject: Re: My latest project - Schematic - Pics (Update)
New postPosted: Wed Jan 14, 2009 11:01 pm 
Offline
Member Number 1
Member Number 1
User avatar

Joined: Fri Jan 05, 2007 8:53 pm
Posts: 1334
Location: South Coast, MA
My Language: English
Some Pictures:


You do not have the required permissions to view the files attached to this post.

_________________
Get your contributing member badge for 2010!
Small Donations Help - PayPal Link
Be sure to note your user name or send me a pm.


Top
 Profile E-mail  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 9 posts ] 

All times are UTC - 5 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
cron
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group